(1) Where an occupancy, an exproprietary or a hereditary tenant has heretofore paid his rent by bighori or batai, or partly by bighori and partly by batai, he may apply for the commutation of such rent to a fixed money rent:
     Provided that in an area where rents are paid by bighori for some crops and by batai for others, the tenant may elect to have that portion of the rent which is payable by batai alone commuted into bighori on the basis of sanctioned rates appropriate to him, and in such case the court shall commute that portion which is payable by batai by fixing a rate of rent per bigha for batai crops grown on the holding.